Williams extended her game winning streak in the tournament to 24 until finally giving up a game to China’s Li Na, eventually winning handily 6-0, 6-3. In the second set Na broke for a 2-1 lead before Williams applied the hammer, winning five of the next six games.

Serena takes her 20-3 record in Slam semifinals into the match against Li. The last time she lost? In 2009 when she imploded after a foot fault call against Kim Clijsters, threatening to shove a ball down a lineswoman’s throat.

The match was marked by an exchange at the net where after a Djokovic touch shot, Nadal ran up and drove a backhand that hit Djokovic in the face after glancing off his racquet. An angry Djokovic turned away from Nadal who was raising his hand in apology, which drew a shrug from Nadal.

Women’s Notes: Sterling field featuring six of the Top 10…Wildcards went to Stosur, Na, and Brits Johanna Konta and Elena Baltacha…Four former Slam champs in the field…Tough starts for (8) Petrova vs. (WC) Stosur, (5) Wozniacki vs. the defending champ Paszek, (7) Ivanovic vs. the crafty Russian Vesnina, and (2) Na vs. Cornet, then either Bartoli or Flavia Pennetta…No. 55-ranked American Christina McHale was the last direct acceptance in the quality field…Pulling from the event were Sara Errani, Yaroslava Shvedova and Sloane Stephens…Former champs in the field are Paszek (2012), Bartoli (2011), Eraterina Makarova (2010), Wozniacki (2009), and Radwanska (2008).

“That’s one of the best wins of my career,” said Mattek-Sands, who hit 32 winners during the aggressive assault. “I knew she wasn’t going to give it to me. She’s a champion, and I had to play some of my best tennis ever to beat her…It was kind of a battle of who can take control of that middle court.”

Notes: Insane field with two former No. 1s and an additional Slam champ all unseeded…The Top 3 seeds are current or former No. 1s…Tough opening-round matches are (5) Na vs. Tamira Paszek then the winner of Venus and (WC) Medina Garrigues, (3) Azarenka vs. Pavlyuchenkova, (11) Petrova vs. a qualifier then likely Kuznetsova, (16) Ivanovic vs. a qualifier then likely her Serb countrywoman Jankovic, (9) Stosur vs. the clay-savvy Suarez Navarro, and (2) Sharapova vs. a qualifier then likely Peng…No blue clay this year…Former champs in the field are Serena Williams (2012) and Kvitova (2011).

“I tried to be ready for Indian Wells but my ankle wasn’t ready, so I had to wait another few weeks,” Na said. “I really wanted to be 100 percent ready to come back to the court, because otherwise it would be dangerous. I’ve been really looking forward to coming back. I feel like I had another off-season just now.”

Djokovic, still on track for what would be an Open Era record third Australian Open title in a row, will in the semifinals meet No. 4 seed David Ferrer, who came back from a set down and more to beat fellow Spaniard Nicolas Almagro 4-6, 4-6, 7-5, 7-6(4), 6-2.